import java.util.Scanner;
/**
 * Created with IntelliJ IDEA
 * Description
 * User：chenshu
 * Date：2023-10-11
 * Time：22:07
 */
public class Work {
    public static void multiForm() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        for(int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= i; j++) {
                System.out.print(i + "*" + j + "=" + (i * j) + " ");
            }
            System.out.println();
        }
    }
    public static void login() {
        String passwd1 = "12345";
        String passwd2 = new String();
        Scanner scan = new Scanner(System.in);
        for (int i = 0; i < 3; i++) {
            passwd2 = scan.nextLine();
            if (passwd1.equals(passwd2)) {
                System.out.println("登录成功");
                break;
            }
        }
        System.out.println("退出程序");
    }
    public static void countBit1() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int tmp = n;
        int count = 0;
        while (tmp != 0) {
            if((tmp & 1) == 1) {
                count++;
            }
            tmp >>>= 1;
        }
        System.out.println("在内存中的存储有"+count + "个'1'");
    }
    public static void printBit() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        System.out.print("奇数位序列为：");
        for (int i = 31; i >= 1; i -= 2) {
            System.out.print(((n >>> i) & 1) + " ");
        }
        System.out.println();
        System.out.print("偶数位序列为：");
        for (int i = 30; i >= 0; i -= 2) {
            System.out.print(((n >>> i) & 1) + " ");
        }
    }
    public static void findGCD() {
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();
        int c = a % b;
        while(c != 0) {
            a = b;
            b = c;
            c = a % b;
        }
        System.out.println(b);
    }
    public static void findNarciNum() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        for (int i = 0; i <= n; i++) {
            int count = 0;
            int tmp = i;
            int sum = 0;
            //1.求位数
            while(tmp != 0){
                count++;
                tmp /= 10;
            }
            //2.判断
            tmp = i;
            while(tmp != 0) {
                sum += Math.pow(tmp % 10, count);
                tmp /= 10;
            }
            if (sum == i) {
                System.out.println(i);
            }
        }
    }
    public static void judgeAge() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        if(n >= 0 && n < 18) {
            System.out.println("少年");
        } else if (n >= 18 && n <= 28) {
            System.out.println("青年");
        } else if (n >= 29 && n <= 55) {
            System.out.println("中年");
        } else {
            System.out.println("老年");
        }
    }
    public static void primeNum() {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int i = 0;
        for (i = 2; i <= Math.sqrt(n); i++) {
            if(n % i == 0){
                System.out.println("no prime number！");
                break;
            }
        }
        if (i > Math.sqrt(n)) {
            System.out.println("yes!");
        }
    }
    public static void main(String[] args) {
        primeNum();
    }
}
